It is often desirable to determine the energies and doses of particles incident on materials exposed to a plasma. For example, the successful design of a fusion reactor based on magnetic confinement requires an understanding of conditions at the boundary region between the magnetically confined plasma and the reactor wall. The particles of interest are usually hydrogen or deuterium with energies and fluxes typically in the range of 10 to 1000 eV and 10.sup.12 to 10.sup.18 particles per square centimeter per second, respectively. In the past, such studies have generally relied on ion beam analysis or sputter profiling measurements to determine the dose and energy of the particles retained in probe samples exposed to the plasma edge. However, such techniques require specialized facilities and considerable effort to perform the analysis. Additionally, ion beam analysis or sputter profiling cannot provide the desired information during exposure of the probe.
A technique for measuring neutron doses is disclosed in U.S. Pat. No. 2,564,626 to MacMahon et al. This device includes a boron, lithium, aluminum or lead element which is exposed to a neutron beam. Changes in the resistance of the element resulting from nuclear transmutation indicate the neutron dose. However, this device cannot be used to detect energetic ions.
Accordingly, it is an object of the present invention to overcome the disadvantages associated with devices and methods known in the prior art.
An object of the invention is to provide a simplified means and method for determining the energy and integrated dose of energetic ions and neutral particles in a plasma.
It is an object of the invention to provide means for obtaining desired information regarding a plasma continuously during exposure of a probe to the plasma.